Dry product, such as pellets, powders, sand, oil sand, and other abrasive materials, may be stored and shipped in bulk containers such as railroad tank cars and tank trailers for transportation from one site, such as a mine, to be delivered to another site, such as a manufacturing plant. The delivered product exits from the storage compartment of the transport carrier or tank trailer, and then flows through piping upon the trailer for delivery by hose or further piping to a storage facility or location of usage. In dry bulk hauling, the seal integrity at the pipe connection is essential to prevent cross contamination of the material sequentially hauled in the tank trailers. It is desirable to provide not only cleansed air that is used in the unloading process, but also to reduce the volume of noise involved in the discharge. The material unloaded from gravity gate valves or hoppers located on the bottom of the tank car, exit through tees that are attached to the bottom of a hopper which normally connect with a collection of pipes, that convey air under pressure to assist in the unloading process. A vacuum or air stream from a pneumatic conveyor system created in the piping system accelerates the unloading of dry bulk products from the hopper.
Presently, the bulk transporting industry favors downloading dry product from tank trailers by pneumatic systems. A pneumatic system begins with a blower mounted to a tractor, such as a truck. When turning at high revolutions per minute, the blower forces air into a discharge pipe that pressurizes the collection pipes below a trailer. The pressurized air then attracts by venturi flow the granular material, by gravity out of the tank trailer, and it is conveyed within the stream of the pressurized flowing air, to the site of storage. The pressurized air then delivers the dry bulk product from the collection pipes to the delivery point, commonly by way of a hose.
The tank trailer has a number of hoppers that each direct dry bulk material through a valve, such as a butterfly valve, into a hopper tee and then into the pressurized line. The line generally discharges towards the rear of the trailer, that is, towards the trailer wheels. After the last hopper, the line requires realignment to pass the rear axles. The line may pass either below or above the rear axles and in doing so, the line has an angular adjustment proximate the last hopper tee. A realigned line may discharge bulk material either in a high position above the axles or a low position beneath the axles. Some unloading arrangements include hoses or metal rear unload lines. Each change in direction calls for a fitting, more particularly an elbow, to realign the straight sections of pipe in the line. Abrasive material can rapidly or prematurely wear pipe and fittings that convey the material. Where a moving abrasive material changes direction of flow, forces accumulate and abrade or wear down a location upon a pipe or fitting. In time, the fitting has a hole worn into it that leaks product from the fitting or the fitting completely fails and discharges product out of the system. It has also been found that abrasive material causes the hoses or the metal rear unload lines to wear out prematurely.
In order to reduce the length of piping required, it is also known to discharge material from a side of the tank trailer. In this arrangement, a bend is connected to the hopper tee in order to direct the material out of the side of the tank trailer. The bend is also subject to wearing out prematurely where abrasive material excessively impacts certain points within the bend during an unloading operation. Although discharging from the side is convenient in some situations, it may be discouraged due to the bend wearing out prematurely and having to be replaced.
Furthermore, known clamps and elbows often have been constructed of cast iron and mild steel parts that corrode from exposure to the environment as a tank trailer, or hopper trailer, travels the roads subject to rain, snow, and deicing compounds. Once corroded, the clamps and elbows become nearly impossible to remove from a pipe. If this occurs then changing the clamp or elbow from beneath a hauler becomes a more difficult task. The driver must pry the corroded elbow from the line with a pry bar or a length of pipe. In some situations, the driver must hammer the elbow carefully to free it from the pipe. It would be desirable to incorporate quick disconnect fittings for the elbows to avoid this situation.
Also, some clamps and elbows having flanges that are not versatile because they do not easily connect or mate to different pipe sections. For example, elbows having flanges can easily connect to other flanged fittings but not to round pipe directly. An elbow may have to connect to a section of pipe that has a female connector or a male connector. In this particular situation, a flange will not be suitable to connect or mate to such a pipe. It would be advantageous to have elbows that easily connect pipes having a female or a male connector.
The present disclosure is designed to obviate and overcome many of the disadvantages and shortcomings experienced with prior discharge configurations. Moreover, the present disclosure is related to an unload elbow with spherical wear pocket that greatly reduces or eliminates the possibility of the unload elbow wearing out prematurely when being impacted by abrasive material or granular material passing through the unload elbow.